The long term goal of this project is to identify the molecular mechanisms involved in the activation of sensory neurons by unsaturated aldehydes, particularly acrolein. -Specific Aim 1. Investigate the responses of TRPA1-/- mice to unsaturated aldehydes The physiological and behavioral responses of both wild-type and TRPA1 knockout mice to acrolein and other unsaturated aldehydes will be studied. The mice will be tested for differences in thermal and mechanical sensitization following application of the irritants. -Specific Aim 2. Identify the mechanisms of acrolein activation of TRPA1 channels Electrophysiological, biochemical and molecular techniques will be employed to determine the mechanism of acrolein activation of TRPA1 channels. An acrolein activation model will help reveal whether TRPA1 is agonized by other unsaturated aldehydes with similar mechanisms of activation. -Specific Aim 3: Analysis of the role of TRPA1 activation during acrolein-mediated bladder cystitis To investigate the interaction of TRPA1 channels with unsaturated aldehydes in internal organs we will use the cyclophosphamide cystitis model. Injection of the chemotherapeutic agent cyclophosphamide leads to the metabolic generation of acrolein that is accumulated in the bladder. Acrolein induces hemorrhagic bladder cystitis through activation of sensory nerve endings in the bladder wall. Induction of this condition in TRPA1-/- mice and wild-type mice will allow for the examination of the role of this channel in the inflammatory process. Behavioral, morphological and physiological studies will be conducted. TRPA1 is a novel cation channel involved in sensory activity and nociception. The aims within this proposal outline experiments that will examine the molecular mechanisms involved in TRPA1 activation by acrolein. Deciphering the mechanisms of TRPA1 activation is relevant to many health related issues. Acrolein is a common environmental irritant as well as a metabolic product of oxidative stress and the targets for most of these compounds on sensory neurons remains unknown. Therefore, the results within this study can provide insight into how a sensory neural channel links an environmental irritant to a biological response.